Integrated environmental response of shaded transitional spaces in hot

climates: the design of the Brazilian veranda

G. Maragno

Federal University of Mato Grosso do Sul, Brazil

Coch, Helena

School of Architecture of Barcelona, Spain

ABSTRACT

Protection from the sun is widely considered to be one of the main bioclimatic strategies in hot

climates or during warm seasons. One of the alternatives to shading is the use of covered transitional

spaces, which have appeared in the architecture of different countries over time and include the

Greek and Roman porticus, the Japanese engawa, the Renaissance loggias, canopies and verandas.

This paper examines how verandas have always been present in the architecture of Brazil, whose

climate is mostly tropical. The veranda has passed through various phases: indigenous constructions,

adaptation to a different climate by the Portuguese in colonial times, the incorporation of the veranda

into the vocabulary of modern architecture and even as a traditional element, and its survival to the

present day as a typical area in Brazilian houses. The presence of a veranda has a direct impact on

the creation of shaded areas and the protection of exterior walls from the sun. However, verandas

also affect other aspects, such as daylighting and ventilation. Despite the recognition of their

environmental contributions, verandas are not usually the determining factor in design, and they are

sometimes ignored or secondary to the functional and aesthetic aims that are almost always

prevalent. Through questionnaires and design analysis, this paper examines the attitudes of Brazilian

architects to the design of the veranda, and assesses how different design strategies affect houses’

responses to climate. Moreover, the research speculates on the potential for reducing energy

consumption through the proper use of the veranda, and the possibility of characterizing it as an

important strategy for sustainability.

1. INTRODUCTION

In tropical climates, warmth is usually due to a combination of high air temperature, humidity, and

rainfall combined with considerable action of solar radiation. The general term "tropical" is used to

describe a range of situations, as tropical climates are not homogeneous. However, in tropical zones,

there is a predominance of seasons with the above characteristics. The rigorous climate of the tropics

can be mitigated by two essential strategies: blocking solar radiation and ensuring air movement, in

other words, by providing shade and fresh air. Shade also acts as an umbrella during heavy

rainfall. Brise-soleils, eaves and other devices are very useful and desirable for creating shade.

Figure 1. Map of tropical climates and the metaphor of the shaded spaces.

However, one specific type of transitional space is adapted to the climate and even extends the

area of sky that is protected when it is overcast: the veranda. People in tropical climates tend to do

many activities outside. They stay outdoors longer to take advantage of breezes and, therefore, they

need protection from the sun and rain.

Verandas as transitional covered spaces directly meet the need for shade and rain protection. As

they are spaces that are open at least on one side, they also provide fresh air and natural light that is

less intense and different to that of the interior.

Ninety-two per cent of Brazil is in the tropical zone. In this country, verandas were introduced by

the Portuguese colonizers as a result of their experience in the Mediterranean. The colonizers were

also influenced by contact with Eastern architecture, mainly from Japan and India, and by the early

solutions adopted by the indigenous peoples. Over time, the veranda was transformed to adapt to the

climate and culture in each region of the country.

Although the veranda is considered a typical solution of traditional architecture, it has been

introduced and widely used in the vocabulary of modern Brazilian architecture, mainly in response to

the use of large glass surfaces. Even today, the veranda is an almost obligatory area of Brazilian

houses. However, precisely because of its recurrence, it is often considered a banal solution to

environmental challenges, and is more highly valued for its contributions to aesthetic and functional

aspects.

2. SHADED TRANSITIONAL SPACES

Many recognized authors agree that the high levels of solar radiation, the illuminance of the sky and

the abundant rainfall in tropical climates make it imperative to protect the building envelope from the

sun and highly desirable to create covered and shaded spaces next to buildings (Olgyay, 1963;

Givoni, 1969; Konya, 1981).

"Space is just a terrible outside-inside" (Bachelard, 2000). However, between the inside and the

outside, the open and closed, there is a boundary that can be defined as consisting of a wall or

something softer, as what occurs over an interval of time, as what happens in transitional spaces. In

architecture, these kinds of spaces cannot be classified as interior or exterior and their existence

cannot be explained in terms of a precise and specific function. They are found worldwide, and

constitute an important element of different architectural typologies (Coch, 2003).

Transitional spaces interact with the interior and exterior, and are also known as interstitial or

intermediate spaces. They are categorized according to their spatial characteristics as semi-outdoor,

semi-open or semi-closed. They are also classified in relation to the degree of integration into the

main part of the building, i.e. they are attached or added (Cadima, 2000). For some authors, the

transitional space is a "mediator, a link between the interior spaces with their controlled light and

climate, and the natural environment with its uncontrolled climate, sun, wind and rain" (Kapstein,

1988).

Shaded transitional spaces, such as courtyards, porticos and balconies, were used in the first

centres of population that led to the first cities. In particular, they can be found in the civilizations of

the great rivers, such as the Mesopotamian, Egyptian, Chinese and Indian cities. Later, in

Mediterranean civilizations that had a less rigorous climate, buildings could be more open to the

outside. Thus, the sun became a factor to be controlled, and spaces were available to take advantage

of the sunbeams in winter, while they were shaded in summer. The Megaron, which was described

by Socrates in the fourth century BC, was one of the main prototypes of this solution. It consisted of

a main floor space closed to the north and opened to the south with a sort of front veranda.

Throughout the history of architecture, innumerable solutions of transitional spaces have been

used worldwide, especially in warm regions. Arcades, porticos, cloisters, loggias, large eaves and

even some shading devices with the extra protection of lattices have been present in the

Mediterranean and in Islamic, Eastern and Indian culture.

Figure 2. Types of transitional spaces and the Megaron.

3. THE BRAZILIAN VERANDA

Verandas are a specific type of transitional space. In addition to acting as a filter between indoors

and outdoors of countless environmental conditions, they represent a specific place in dwellings.

While they are not an architectural element that is unique to Brazil, their considerable presence in

buildings in almost all Brazilian regions and periods of history has had a significant impact on

Brazilian architecture.

From an environmental perspective, the veranda can be summed up as a habitable, covered

transitional space that is added to a building and open to the exterior on one or more sides. It protects

both the building envelope and the space that it creates from rain and unwanted radiation. The

veranda is ventilated with fresh outside air and illuminated with less intense light than the exterior.

This light is different to that found in the indoor areas to which the veranda is linked.

The veranda was brought to Brazil as a result of colonization by the Portuguese. It is possible to

distinguish various sources of inspiration in the veranda: aspects inherited from Greek and Roman

architecture adapted to the Mediterranean climate; Arab influence, due to the long period in which

the Iberian Peninsula was under Arab rule; and, particularly in the case of Brazil, contact with

Eastern cultures, above all those of India and Japan, during the period of great sea voyages. When

the veranda was introduced into Brazil, it was also influenced by the architecture of Brazilian

indigenous peoples, who created spaces to protect themselves from the sun and rain.

Figure 3: A shaded space built by indigenous peoples, a colonial veranda and a modern veranda in Brazil

The climate is considered the physical factor that has had most impact on Brazilian architecture

(Bruand, 1981). This is the probably why the veranda has been present in virtually all ages and stages

of the country's architecture. In addition to this main function of responding to the climate, the

veranda has acquired many other functions that have given it particular value and meaning. It has

survived countless cultural, social and economic transformations, and even changes in aesthetic

appreciation.

Although the veranda is a typical feature of traditional architecture, it was widely used during the

period in which modern architecture spread in Brazil in the first half of the twentieth century. It

became a specific, almost indispensible place in Brazilian houses that is present in all social

classes. Obstacles such as limited space and budgets tend to be overcome. Today, the veranda can be

found in homes and flats and its size is increasing. It often constitutes the real living area of a

dwelling.

4. ENVIRONMENTAL EFFECTS OF THE VERANDA

Due to the fundamental impact of solar radiation on buildings’ thermal balance, and consequently on

their heat gain, shading is a primary strategy for obtaining comfort in hot climates. The veranda

shades the building envelope and thus eliminates the action of sunlight on it, in the same way as a

brise-soleil or other shading devices. However, the space created by the veranda itself also prevents

sunlight from acting directly on people and thus reduces the uncomfortable sensation of heat that this

causes. Therefore, verandas constitute a type of pavilion used to generate useful shaded spaces, in

which important functions of the dwelling can be carried out due to the protection from sunlight and

rain and the major advantages of natural ventilation and lighting.

Felt temperature can be taken as the average of air temperature and radiant temperature, under the

same ventilation conditions. Shaded spaces significantly decrease the proportion that corresponds to

radiant temperature. Consequently, verandas reduce the felt temperature, which is further decreased

by the action of the ventilation.

The radiation that is incident on a building consists of a sum of different elements. Direct solar

radiation is the most obvious and important factor, especially when the sky is clear. However, diffuse

and reflected radiation also provides heat, as does the radiation that is emitted by surfaces and objects

in the vicinity due to warming under the action of solar radiation. The veranda always has an impact,

as it reduces the area of solar radiation exposure. Some aspects of its location and design, such as its

latitude, orientation, degree of insertion into the building mass, the relationship between its height

and depth, and other factors, may make it more or less effective at providing protection from solar

radiation. Rainfall is usually abundant in tropical climates, so verandas also act as large umbrellas.

Their effectiveness is dependent on the relationship between their height and depth and the angle of

the rainfall.

In many tropical climates, the direct cause of discomfort is the high humidity combined with high

temperature, which leads to a feeling of extreme mugginess (Serra 1999). Air movement near the

body alleviates discomfort, as it increases heat loss by convection and reduces the sensation of

heat. The veranda plays an important role in air movement, as it enables fresh air to enter the house,

allows windows to remain open even when it is raining, and creates its own shaded and ventilated

space.

Similarly, as a transitional and perimeter space, verandas affect the distribution of daylight from

outside to inside. However, we often forget that visual comfort depends more on the relationship

between the different sources of light in the visual field than on the amount of light. Therefore, the

veranda plays an essential role in tropical climates, where there is an extremely high amount of light.

It stops direct sunlight from entering buildings and reduces the absolute amount of light, which helps

to reduce contrasts and unwanted glare. The depth of the veranda and the reflective characteristics of

its surfaces are the main design factors in these aspects.

Figure 4: The environmental impact of verandas: solar radiation, rainfall and air movement.

Verandas can also affect sound radiation, although their impact on this aspect is limited by the

fact that they are open spaces. A veranda can be equipped with screens that reflect sound back

outside or back inside, depending on which sounds are undesirable or desirable. Combinations of

depth and the use of surfaces materials that absorb sound can help to absorb noise.

Verandas have many effects on environmental aspects, which essentially vary according to design

factors.

5. DESIGN AND USE OF VERANDAS IN BRAZIL

The period in which modern architecture spread in Brazil, from 1930 to 1950, was marked by

constructions that took climate needs into consideration. However, in the following years, this

attention to climatic factors diminished and adaptation to the climate response became the exception

rather than the norm in Brazilian architecture. The current generation of architects is progressing

with new languages and the incorporation of innovative materials and structural solutions. However,

this generation is also influenced and inspired by the modernist projects of the aforementioned

period.

An environmental approach has again been used in many designs, although often empirically or as

a result of other intentions, such as the creation of spaces for living and leisure and aesthetic

solutions. To a greater or lesser extent, it is possible to interpret the design of verandas as a call to be

in contact with nature and, increasingly, a search for aesthetic qualities associated with sustainability.

Nevertheless, strong concepts of sustainability have not yet been effectively incorporated into

practice.

Decisions related to the aesthetics of a building have an impact on environmental aspects. We

studied the presence and characteristics of the design of the veranda in recent Brazilian

architecture. The buildings we analysed were based on two books about recent production of

Brazilian architecture: Brazilian House (Segre, 2006), Ainda Moderno: arquitetura brasileira

contemporanea (Cavalcanti & Lake, 2005), and 2008-2009 editions of the two most prestigious

Brazilian architectural magazines: AU and Projeto. We also carried out a qualitative study, on the

basis of interviews with Brazilian architects, and a quantitative study, through surveys of architects

from around the country and ordinary users of verandas.

The study of the buildings allowed us to identify eight basic strategies employed by architects in

the design of verandas. These are: increasing the amount of covered area, adding new covered areas,

reducing the built area, setting the walls back, pilotis, structural interspaces, interconnection and

verandas that can be opened up or closed. A ninth general strategy is related to verandas in vertical

apartment blocks. Some strategies facilitate the generation of verandas that jut out from the main

building, while others create embedded verandas. In addition, each strategy provides shade,

ventilation and lighting, to varying degrees.

The qualitative study highlighted the presence of the veranda in Brazilian architecture and the fact

that verandas are designed without a suitable study of environmental factors. Although architects

acknowledge their role in this area, they are much more focused on aesthetic and functional aims

than on adaptation to the climate. In addition, many of them are not aware of the role that verandas

play in their constructions, and are even surprised by this finding.

Figure 5: Veranda design strategies: increase of covered area, adding new covered and reducing the building area.

Figure 6: Veranda design strategies: setting the walls back, pilotis and structural spaces

Figure 7: Veranda design strategies: interconnection, verandas that can be opened out or closed and verandas in

vertical apartment blocks.

The quantitative study highlighted the importance of the veranda in Brazil, both for its users and

the architects. All the users considered that the veranda was important or very important to the

houses. The study also noted that there was an overlap in the activities planned by architects for

verandas and those actually carried out by users. It was emphasized that this is a great space to live,

rest and spend free time in Brazilian homes.

6. CONCLUSIONS

The results of the survey, along with the contents of the interviews and the collection of works

that were analyzed, confirm the presence of the veranda and its importance to users and architects.

However, the architects are not always clearly aware of its role, even though they use this element

frequently in their projects. Its multiple functions, the apparent simplicity of construction and its

banality due to repetitive use somehow mask its key role in the play of light and shadow, which is

also embodied in its dual nature: visual aspects and thermal-lighting aspects.

The shade generated by verandas make spaces more habitable in hot climates. Verandas also

intensify or diminish aesthetic effects, emphasize or hide volumes, evaluate solutions, provide

lightness and depth, among other factors. In addition, we should consider their environmental

performance: the protection of the building envelope and consequently the interior, and the

protection of the space created by the veranda itself.

Verandas have an impact on solar radiation, rain, air movement, lighting and acoustics. The

veranda interacts with each of these factors, although it can only control sound to a certain extent,

due to the fact that it is an open space. As architects devote more attention to an environmental

approach and integrate these aspects into their designs, the contribution of the veranda to the

environmental conditions of Brazilian houses should increase and, consequently, lead to greater

sustainability.

ACKNOWLEDGMENTS

The first author thanks CAPES/Brazil (Coordenação de Aperfeiçoamento de Pessoal de Nível

Superior), and UFMS/Brazil (Universidade Federal de Mato Grosso do Sul) for supporting the

doctoral research.

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